Is this just on the front end. If you unpublish now you should see in the editor view a yellow bar the main ribbon at the top saying it's expired. Is this now showing as well or just on the front end of the site? If so it's likely the code for rendering the page our isn't checking if it's published. If the code is loading pages directly you can use http://www.jondjones.com/learn-episerver-cms/episerver-developers-guide/episerver-api-explained/how-to-check-if-an-episerver-page-is-published-or-not or if you're loading a collection of pages you should be using FilterForVisitor.Filter